Dynamics of Entangled Polymers Confined between Graphene Oxide Sheets as Studied by Neutron Reflectivity
Ki-In Choi, Tae-Ho Kim, Guangcui Yuan, Sushil K. Satija, Jaseung Koo
For graphene-based composites, polymer dynamics confined between graphene sheets is a key parameter governing the oeverall mechanical properties of the bulk materials. Here, we used neutron reflectivity to measure the diffusion dynamics of polymer melts confined between graphene oxide (GO) surfaces. To investigate the polymer mobility as a function of distance from the GO surface, we prepared a series of bilayers of hydrogenated/deuterated polymers with varying thicknesses sandwiched between GO monolayers and measured the in-situ neutron reflectivity as a function of annealing time above their glass transition temperatures. From the results, we found that the diffusion coefficients of poly(methyl methacrylate)(PMMA) between the GO sheets were dramatically more than one order reduced when the film thickness is less than approximately 3 times the gyration radius of the bulk polymer (Rg), whereas the diffusion of polystyrene (PS) films sandwich between the GO sheets was only 3 time slower as decreasing the PS thickness from 8 Rg to 1 Rg. This difference is due to the fact that the polymer-GO interaction significantly influences on the dynamics of confined polymer melts.
, Kim, T.
, Yuan, G.
, Satija, S.
and Koo, J.
Dynamics of Entangled Polymers Confined between Graphene Oxide Sheets as Studied by Neutron Reflectivity, ACS Macro Letters, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=923645
(Accessed February 22, 2024)